The Human Phospholipase B-II Precursor (HPLBII-P) in Urine as a Novel Biomarker of Glomerular Activity in COVID-19 and Diabetes Mellitus (preprint)

The human phospholipase B-II precursor (HPLBII-P) was originally purified from white blood cells but is also found in other cellular structures such as kidney glomeruli and tubuli. The objective of this report was to investigate the relationship of HPLBII-P in urine to acute kidney injury in patients with COVID-19 Methods Urine was collected at admission from 132 COVID-19 patients admitted to the intensive care units (ICU) because of respiratory failure. HPLBII-P was measured by a sensitive ELISA. For comparison, HNL was measured in urine, by the ELISA configured with mabs 763/8F, as a sign of tubular affection in addition to routine biomarkers of kidney disease Results Overall, the concentrations of urinary HPLBII-P were almost 3-fold higher in COVID-19 patients as compared to healthy controls (p

SARS-CoV-2 3CLpro Main Protease Drives Cytoskeletal Reorganization and Tunnelling Nanotube Formation for Stealth Intercellular Infection (preprint)

To identify and characterize roles for SARS-CoV-2 3CLpro main protease in promoting viral infection and dissemination, we employed Inactive Catalytic Domain Capture and proteomics to identify host cell interactors and substrates in the interactome of 3CLpro. Of 259 3CLpro interactors, 145 were associated with the cytoskeleton and its organisation. We determined enzyme kinetic specificity constants for 139 3CLpro cut-sites in 43 interactors using a multiplex assay, identifying 29 efficiently-cleaved substrates and validating 13 as substrates in vitro, in SARS-CoV-2-infected human lung cells, and in COVID-19 post-mortem lungs. 3CLpro cleavage of adherens junction proteins initiated cytoskeletal rearrangement, activated zonular signalling, removed subcellular localization motifs to trigger translocation of nuclear TRIM28 and NUMA1 to adherens junctions, and YAP1 in the hippo pathway, to the nucleus. These cytoskeletal remodelling events rapidly generated tunnelling nanotubes connecting lung epithelial cells and containing virus colocalized with 3CLpro substrates for stealth trafficking of SARS-CoV-2 to distant cells.

The protein expression profile of ACE2 in human tissues (preprint)

The novel SARS-coronavirus 2 (SARS-CoV-2) poses a global challenge on healthcare and society. For understanding the susceptibility for SARS-CoV-2 infection, the cell type-specific expression of the host cell surface receptor is necessary. The key protein suggested to be involved in host cell entry is Angiotensin I converting enzyme 2 (ACE2). Here, we report the expression pattern of ACE2 across >150 different cell types corresponding to all major human tissues and organs based on stringent immunohistochemical analysis. The results were compared with several datasets both on the mRNA and protein level. ACE2 expression was mainly observed in enterocytes, renal tubules, gallbladder, cardiomyocytes, male reproductive cells, placental trophoblasts, ductal cells, eye and vasculature. In the respiratory system, the expression was limited, with no or only low expression in a subset of cells in a few individuals, observed by one antibody only. Our data constitutes an important resource for further studies on SARS-CoV-2 host cell entry, in order to understand the biology of the disease and to aid in the development of effective treatments to the viral infection.